It would probably be nicer if you strip and stain darker rather than painting. You would need a paint and varnish stripper (see Citristrip). Then get a color stain you prefer. Lastly varnish in order to protect the wood.

If you like these pieces, perhaps show whole space and we can brainstorm how to incorporate them...?

If you don't have much experience refinishing furniture, have them professisonally done.

I am in the middle of a kitchen/dining/living room renovation, which include the red oak floors being refinished in a walnut-Jacobean colour. The new open concept means the accent furniture, ( 4 pieces total that run throughout the house) would fit much better a richer, deeper colour. My walls are BM revere pewter, hallways are BM Pale Oak, and my kitchen is espresso shaker doors with aria Quartz counters . ( sorry no pics yet). I just really like my tables and would like to breath new life into them. I have considered trying BM Avance, which is used to paint kitchen cabinets.

It would cost more to have them redone professionally then to replace them ( I checked :( ) , so it's gonna be a do-it-yourself for sure. Question is to strip and re-stain, or paint...

Since you're going to have to do it yourself, spend some time watching videos on youtubee on how to do it. There are hundreds if not thousands showing how to do everything you can ever imagine. My husband watches a lot of them as we've been renovating our house, and he's doing most of the work. He's found them very helpful in answering all his questions.